The present invention relates to reeling of fiber webs in a fiber web machine. More especially the present invention relates to a method in a turn-up device of reeling the web with a reeling drum of the reel-up onto a parent roll, in which, when the parent roll has reached the desired diameter size, reeling is changed from the parent roll onto a new parent roll by cutting the web by a jet cutting means and the beginning part of the cut web is directed onto a reeling shaft of a new parent roll.
As known from the prior art, fiber web producing processes typically comprise an assembly formed by a number of apparatuses arranged consecutively in the process line. A typical production and treatment line comprises a head box, a wire section and a press section as well as a subsequent drying section and a reel-up. The production and treatment line can further comprise finishing devices, for example a calender and/or a coater. The production and treatment line also comprises typically at least one slitter-winder for forming customer rolls as well as a roll packaging apparatus.
The reel-up is a device which reels a material produced as a continuous fibrous web into the reel form as a machine reel. In the production process of the fiber web, reeling-up is usually the first sub-process in which continuous production is interrupted to continue in sequences. A machine reel is formed around a reel spool operating as the reeling core i.e. the fibrous web being on one machine reel has a start and an end. The trend in the field is a continuous increase in the size of machine reels, which causes an on-going development requirement for reel-ups. The dimensioning of the reel spool specifies the maximum size of the machine reel in practice. However, as we are concerned with a dynamic environment and the fiber web is reel-able material sensitive to various faults, the task performed by the reel-up as the maintainer of the efficiency of the paper or board machine is very considerable. A reason behind the continuous increase in the size of machine reels is the desire to obtain fewer starts and ends in the production of the fibrous web, which impede or disturb the production and decrease the efficiency.
In the reel-up of a continuously operating fiber web machine or a finishing part, for example a coating part, or equivalent, when the parent (machine) roll to be reeled becomes full or reaches the desired size, the fiber web is changed from the full roll onto a reeling shaft for beginning of reeling of a new parent roll typically at full running speed of the machine. In such a case from the cutting-off of the fiber web and from its change onto the new reeling shaft for beginning of reeling of the new parent roll, reliability of operation is required in order that the operation does not have to be interrupted.
It is well-known from prior art to use a water jet to cut the fibrous web by a special device. The device according to U.S. Pat. No. 6,135,000 which is incorporated by reference herein, comprises at least one, preferably two carriages, which are moved on a guide bar and which comprise nozzles that move along with the carriage for shooting the water jet(s) to cut the moving fibrous web. In addition to the moving nozzles, the device also comprises moving hose wheels, the purpose of which is to keep the high-pressure hoses, which lead to the nozzles, directly conveyed during the fast movement of the carriage. The longitudinal feed of the hose is synchronously connected to the movement of the carriage and the feed can be controlled both during the cutting and the return movement.
In U.S. Pat. No. 5,360,179, which is incorporated by reference herein shows a method and a device for reeling a web, i.e., a turn-up. A device is described wherein the web is reeled by a reeling drum onto a parent roll, whereby when the parent roll has reached the desired diameter size, new reeling is started from the parent roll of desired size onto a new parent roll. After the parent roll has reached the desired diameter size, a tip part is cut into the web by means of a water jet or water jets and the tip part is blown into contact with a reeling shaft of the new parent roll, whereupon the web is cut off by means of the water jet or water jets. In this prior art arrangement the publication describes a means with two water jets used in cutting a web, and references cutting with one water jet but not actual means are taught. The cutting path with one water jet shown in FIG. 2C is in many cases impossible or at least very difficult in practice since there is no room for the nozzle movement all the way from one edge to another edge due to different components of the reel-up located at the sides. Thus the areas near the edge cannot be cut by the water jets and the web tears uncontrollably and increases the risk of web break or other disturbances. The arrangement with two nozzles as shown in FIG. 1 and the cutting paths shown in FIGS. 2A-2B require two sets of equipment including for example two slides, two motors and two cutting modules, one for each nozzle and cutting path. In these prior art arrangements the linear module has a restricted length due to other components of the reel-up for example due to the space needed for reel spool storage lowering arms and thus the cut does not reach the edges of the web without complicated special arrangements. One disadvantage of these prior art arrangements is that the cutting pressure for the nozzle(s) is raised to the right cutting level only after the nozzle(s) has moved and been on the web already some time and the waiting time for the right pressure level causes broke. This is critical especially when cutting thicker fiber webs, e.g., board, since there the waiting time is longer since it is critical that the cutting pressure is correct when the cutting is begun otherwise the web is not cut or it tears uncontrollably.
In Fl patent 120445 is described an arrangement for a water jet turn-up device in which the beam for a nozzle(s) is movable and/or turnable from a cutting position to maintenance position for changing the nozzles of the water jet turn-up device and for other maintenance actions to the device.
If a nozzle of a water jet turn-up device is not functioning it has to be changed and the web has to be cut manually and the reel-up has to be stopped at least partially for the change of the nozzles. As this causes a break in production it needs to be done as fast as possible to minimize the break time.